A1 Journal article (refereed), original research

Fatigue strength assessment of ultra-high-strength steel fillet weld joints using 4R method


Open Access publication

Publication Details
Authors: Ahola Antti, Skriko Tuomas, Björk Timo
Publisher: Elsevier
Publication year: 2019
Language: English
Related Journal or Series Information: Journal of Constructional Steel Research
ISSN: 0143-974X
eISSN: 1873-5983
JUFO-Level of this publication: 2
Open Access: Open Access publication
Location of the parallel saved publication: http://urn.fi/URN:NBN:fi-fe202001273594

Abstract

A fatigue analysis on experimentally tested transverse fillet-welded
non-load-carrying T- and X-joints made of S960 and S1100
ultra-high-strength steel was carried out in the present study. The test
data consisted of welded joints in the as-welded, high frequency
mechanical impact-treated, and tungsten inert gas-dressed conditions,
that were fatigue tested using uniaxial constant amplitude loading with
an applied stress ratio of R = 0.1–0.5. The weld geometry and
residual stress measurements were carried out, and for each joint, the
fatigue strength was assessed using a multiparametric notch stress
approach, entitled the 4R method, which incorporates the consideration
of four parameters, i.e. notch stress range Δσk(r), applied stress ratio R, material ultimate strength Rm, and residual stress σres
in the fatigue assessment. In the 4R method, the local cyclic
elastic-plastic behavior at the notch root is obtained, and the
Smith-Watson-Topper parameter is applied to conduct a mean stress
correction to commeasure all results into a single S-N
curve. The results showed that the applied stress ratio had a distinct
influence on the fatigue strength capacity for both joints in the
as-welded and post-weld treated conditions when using the conventional
stress-based approaches, i.e. nominal stress, structural hot-spot stress
and effective notch stress concepts. Nevertheless, the 4R method
resulted in a good agreement between the experimental test results and
the fatigue strength assessments, regardless of the load and joint
conditions.


Last updated on 2020-20-03 at 10:03